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/*
* Rest in pieces - RIP protocol
*
* Copyright (c) 1999 Pavel Machek <pavel@ucw.cz>
*
* Bug fixes by Eric Leblond <eleblond@init-sys.com>, April 2003
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#undef LOCAL_DEBUG
#include "nest/bird.h"
#include "nest/iface.h"
#include "nest/protocol.h"
#include "nest/route.h"
#include "lib/socket.h"
#include "lib/resource.h"
#include "lib/lists.h"
#include "lib/timer.h"
#include "lib/md5.h"
#include "lib/string.h"
#include "rip.h"
#define P ((struct rip_proto *) p)
#define P_CF ((struct rip_proto_config *)p->cf)
#define PACKETLEN(num) (num * sizeof(struct rip_block) + sizeof(struct rip_packet_heading))
/*
* rip_incoming_authentication - check authentication of incomming packet and return 1 if there's problem.
*/
int
rip_incoming_authentication( struct proto *p, struct rip_block_auth *block, struct rip_packet *packet, int num, ip_addr whotoldme )
{
DBG( "Incoming authentication: " );
switch (ntohs(block->authtype)) { /* Authentication type */
case AT_PLAINTEXT:
{
struct password_item *passwd = get_best_password( P_CF->passwords, 0 );
DBG( "Plaintext passwd" );
if (!passwd) {
log( L_AUTH "No passwords set and password authentication came" );
return 1;
}
if (strncmp( (char *) (&block->packetlen), passwd->password, 16)) {
log( L_AUTH "Passwd authentication failed!" );
DBG( "Expected %s, got %.16s\n", passwd->password, &block->packetlen );
return 1;
}
}
return 0;
case AT_MD5:
DBG( "md5 password" );
{
struct password_item *head;
struct rip_md5_tail *tail;
if (ntohs(block->packetlen) != PACKETLEN(num) - sizeof(struct rip_md5_tail) ) {
log( L_ERR "Packet length in MD5 does not match computed value" );
return 1;
}
tail = (struct rip_md5_tail *) ((char *) packet + (ntohs(block->packetlen) ));
if ((tail->mustbeFFFF != 0xffff) || (tail->mustbe0001 != 0x0100)) {
log( L_ERR "MD5 tail signature is not there" );
return 1;
}
head = P_CF->passwords;
while (head) {
DBG( "time, " );
if ((head->from > now) || (head->to < now))
goto skip;
if (block->seq) {
struct neighbor *neigh = neigh_find(p, &whotoldme, 0);
if (!neigh) {
log( L_AUTH "Non-neighbour MD5 checksummed packet?" );
} else {
if (neigh->aux > block->seq) {
log( L_AUTH "MD5 protected packet with lower numbers" );
return 0;
}
neigh->aux = block->seq;
}
}
DBG( "check, " );
if (head->id == block->keyid) {
struct MD5Context ctxt;
char md5sum_packet[16];
char md5sum_computed[16];
memset(md5sum_packet,0,16);
memcpy(md5sum_packet, tail->md5, 16);
password_strncpy(tail->md5, head->password, 16);
MD5Init(&ctxt);
MD5Update(&ctxt, (char *) packet, ntohs(block->packetlen) + sizeof(struct rip_block_auth) );
MD5Final(md5sum_computed, &ctxt);
if (memcmp(md5sum_packet, md5sum_computed, 16))
return 1;
return 0;
}
skip:
head = head->next;
}
return 1;
}
}
return 0;
}
/*
* rip_outgoing_authentication - append authentication information to the packet.
* %num: number of rip_blocks already in packets. This function returns size of packet to send.
*/
int
rip_outgoing_authentication( struct proto *p, struct rip_block_auth *block, struct rip_packet *packet, int num )
{
struct password_item *passwd = get_best_password( P_CF->passwords, 0 );
if (!P_CF->authtype)
return PACKETLEN(num);
DBG( "Outgoing authentication: " );
if (!passwd) {
log( L_ERR "No suitable password found for authentication" );
return PACKETLEN(num);
}
block->authtype = htons(P_CF->authtype);
block->mustbeFFFF = 0xffff;
switch (P_CF->authtype) {
case AT_PLAINTEXT:
password_strncpy( (char *) (&block->packetlen), passwd->password, 16);
return PACKETLEN(num);
case AT_MD5:
{
struct rip_md5_tail *tail;
struct MD5Context ctxt;
static u32 sequence = 0;
if (num > PACKET_MD5_MAX)
bug( "We can not add MD5 authentication to this long packet" );
/* need to preset the sequence number to a sane value */
if(!sequence)
sequence = (u32) time(NULL);
block->keyid = passwd->id;
block->authlen = sizeof(struct rip_block_auth);
block->seq = sequence++;
block->zero0 = 0;
block->zero1 = 0;
block->packetlen = htons(PACKETLEN(num));
tail = (struct rip_md5_tail *) ((char *) packet + PACKETLEN(num) );
tail->mustbeFFFF = 0xffff;
tail->mustbe0001 = 0x0100;
memset(tail->md5,0,16);
password_strncpy( tail->md5, passwd->password, 16 );
MD5Init(&ctxt);
MD5Update(&ctxt, (char *) packet, PACKETLEN(num) + sizeof(struct rip_md5_tail));
MD5Final(tail->md5, &ctxt);
return PACKETLEN(num) + block->authlen;
}
default:
bug( "Unknown authtype in outgoing authentication?" );
}
}
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